gold: Handle R_X86_64_CODE_4_GOTPCRELX

Handle R_X86_64_CODE_4_GOTPCRELX and convert

	mov	name@GOTPCREL(%rip), %r31

to

	lea	name@GOTPCREL(%rip), %r31

if the instruction is encoded with the REX2 prefix when possible.

elfcpp/

	* x86_64.h (R_X86_64_CODE_4_GOTPCRELX): New.

gold/

	* x86_64.cc (Target_x86_64::can_convert_mov_to_lea): Handle
	R_X86_64_CODE_4_GOTPCRELX.
	(Target_x86_64::Scan::get_reference_flags): Likewise.
	(Target_x86_64::Scan::local): Likewise.
	(Target_x86_64::Scan::possible_function_pointer_reloc): Likewise.
	(Target_x86_64::Scan::global): Likewise.
	(Target_x86_64::Relocate::relocate): Likewise.
	* testsuite/x86_64_mov_to_lea1.s: Add a test for
	R_X86_64_CODE_4_GOTPCRELX.
	* testsuite/x86_64_mov_to_lea2.s: Likewise.
	* testsuite/x86_64_mov_to_lea3.s: Likewise.
	* testsuite/x86_64_mov_to_lea4.s: Likewise.
	* testsuite/x86_64_mov_to_lea5.s: Likewise.
	* testsuite/x86_64_mov_to_lea.sh: Updated.

diff --git a/elfcpp/x86_64.h b/elfcpp/x86_64.h
index 0377e77..97a87ae 100644 (file)
--- a/elfcpp/x86_64.h
+++ b/elfcpp/x86_64.h
@@ -95,9 +95,13 @@ enum
   R_X86_64_PC32_BND = 39,  // PC relative 32 bit signed with BND prefix
   R_X86_64_PLT32_BND = 40, // 32 bit PLT address with BND prefix
   R_X86_64_GOTPCRELX = 41, // 32 bit signed PC relative offset to GOT
-                          // without REX prefix, relaxable.
+                          // without REX nor REX2 prefixes, relaxable.
   R_X86_64_REX_GOTPCRELX = 42, // 32 bit signed PC relative offset to GOT
                               // with REX prefix, relaxable.
+  R_X86_64_CODE_4_GOTPCRELX = 43, // 32 bit signed PC relative offset to
+                                 // GOT if the instruction starts at 4
+                                 // bytes before the relocation offset,
+                                 // relaxable.
   // GNU vtable garbage collection extensions.
   R_X86_64_GNU_VTINHERIT = 250,
   R_X86_64_GNU_VTENTRY = 251

diff --git a/gold/testsuite/x86_64_mov_to_lea.sh b/gold/testsuite/x86_64_mov_to_lea.sh
index 1b30e1a..3e248eb 100755 (executable)
--- a/gold/testsuite/x86_64_mov_to_lea.sh
+++ b/gold/testsuite/x86_64_mov_to_lea.sh
@@ -25,20 +25,36 @@
 set -e
 
 grep -q "lea    -0x[a-f0-9]\+(%rip),%rax" x86_64_mov_to_lea1.stdout
+grep -q "lea    -0x[a-f0-9]\+(%rip),%r26" x86_64_mov_to_lea1.stdout
 grep -q "lea    -0x[a-f0-9]\+(%rip),%rax" x86_64_mov_to_lea2.stdout
+grep -q "lea    -0x[a-f0-9]\+(%rip),%r26" x86_64_mov_to_lea2.stdout
 grep -q "lea    -0x[a-f0-9]\+(%rip),%rax" x86_64_mov_to_lea3.stdout
+grep -q "lea    -0x[a-f0-9]\+(%rip),%r26" x86_64_mov_to_lea3.stdout
 grep -q "lea    -0x[a-f0-9]\+(%rip),%rax" x86_64_mov_to_lea4.stdout
+grep -q "lea    -0x[a-f0-9]\+(%rip),%r26" x86_64_mov_to_lea4.stdout
 grep -q "lea    -0x[a-f0-9]\+(%rip),%rax" x86_64_mov_to_lea5.stdout
+grep -q "lea    -0x[a-f0-9]\+(%rip),%r26" x86_64_mov_to_lea5.stdout
 grep -q "lea    -0x[a-f0-9]\+(%rip),%rax" x86_64_mov_to_lea6.stdout
+grep -q "lea    -0x[a-f0-9]\+(%rip),%r26" x86_64_mov_to_lea6.stdout
 grep -q "mov    0x[a-f0-9]\+(%rip),%rax" x86_64_mov_to_lea7.stdout
+grep -q "mov    0x[a-f0-9]\+(%rip),%r26" x86_64_mov_to_lea7.stdout
 grep -q "mov    0x[a-f0-9]\+(%rip),%rax" x86_64_mov_to_lea8.stdout
+grep -q "mov    0x[a-f0-9]\+(%rip),%r26" x86_64_mov_to_lea8.stdout
 grep -q "lea    -0x[a-f0-9]\+(%rip),%rax" x86_64_mov_to_lea9.stdout
+grep -q "lea    -0x[a-f0-9]\+(%rip),%r26" x86_64_mov_to_lea9.stdout
 grep -q "lea    -0x[a-f0-9]\+(%rip),%rax" x86_64_mov_to_lea10.stdout
+grep -q "lea    -0x[a-f0-9]\+(%rip),%r26" x86_64_mov_to_lea10.stdout
 grep -q "mov    0x[a-f0-9]\+(%rip),%rax" x86_64_mov_to_lea11.stdout
+grep -q "mov    0x[a-f0-9]\+(%rip),%r26" x86_64_mov_to_lea11.stdout
 grep -q "mov    0x[a-f0-9]\+(%rip),%rax" x86_64_mov_to_lea12.stdout
+grep -q "mov    0x[a-f0-9]\+(%rip),%r26" x86_64_mov_to_lea12.stdout
 grep -q "lea    -0x[a-f0-9]\+(%rip),%rax" x86_64_mov_to_lea13.stdout
+grep -q "lea    -0x[a-f0-9]\+(%rip),%r26" x86_64_mov_to_lea13.stdout
 grep -q "lea    -0x[a-f0-9]\+(%rip),%rax" x86_64_mov_to_lea14.stdout
+grep -q "lea    -0x[a-f0-9]\+(%rip),%r26" x86_64_mov_to_lea14.stdout
 grep -q "mov    0x[a-f0-9]\+(%rip),%eax" x86_64_mov_to_lea15.stdout
+grep -q "mov    0x[a-f0-9]\+(%rip),%r26d" x86_64_mov_to_lea15.stdout
 grep -q "mov    0x[a-f0-9]\+(%rip),%eax" x86_64_mov_to_lea16.stdout
+grep -q "mov    0x[a-f0-9]\+(%rip),%r26d" x86_64_mov_to_lea16.stdout
 
 exit 0

diff --git a/gold/testsuite/x86_64_mov_to_lea1.s b/gold/testsuite/x86_64_mov_to_lea1.s
index 4dce487..298ede1 100644 (file)
--- a/gold/testsuite/x86_64_mov_to_lea1.s
+++ b/gold/testsuite/x86_64_mov_to_lea1.s
@@ -8,4 +8,5 @@ foo:
        .type   _start, @function
 _start:
        movq    foo@GOTPCREL(%rip), %rax
+       movq    foo@GOTPCREL(%rip), %r26
        .size   _start, .-_start

diff --git a/gold/testsuite/x86_64_mov_to_lea2.s b/gold/testsuite/x86_64_mov_to_lea2.s
index 2a11b7a..404f4c1 100644 (file)
--- a/gold/testsuite/x86_64_mov_to_lea2.s
+++ b/gold/testsuite/x86_64_mov_to_lea2.s
@@ -3,4 +3,5 @@
        .type   _start, @function
 _start:
        movq    _DYNAMIC@GOTPCREL(%rip), %rax
+       movq    _DYNAMIC@GOTPCREL(%rip), %r26
        .size   _start, .-_start

diff --git a/gold/testsuite/x86_64_mov_to_lea3.s b/gold/testsuite/x86_64_mov_to_lea3.s
index ac43b78..838c33e 100644 (file)
--- a/gold/testsuite/x86_64_mov_to_lea3.s
+++ b/gold/testsuite/x86_64_mov_to_lea3.s
@@ -7,4 +7,5 @@ foo:
        .type   _start, @function
 _start:
        movq    foo@GOTPCREL(%rip), %rax
+       movq    foo@GOTPCREL(%rip), %r26
        .size   _start, .-_start

diff --git a/gold/testsuite/x86_64_mov_to_lea4.s b/gold/testsuite/x86_64_mov_to_lea4.s
index 37bee32..a68a4cf 100644 (file)
--- a/gold/testsuite/x86_64_mov_to_lea4.s
+++ b/gold/testsuite/x86_64_mov_to_lea4.s
@@ -9,4 +9,5 @@ foo:
        .type   _start, @function
 _start:
        movq    foo@GOTPCREL(%rip), %rax
+       movq    foo@GOTPCREL(%rip), %r26
        .size   _start, .-_start

diff --git a/gold/testsuite/x86_64_mov_to_lea5.s b/gold/testsuite/x86_64_mov_to_lea5.s
index e793a2b..e818989 100644 (file)
--- a/gold/testsuite/x86_64_mov_to_lea5.s
+++ b/gold/testsuite/x86_64_mov_to_lea5.s
@@ -9,4 +9,5 @@ foo:
        .type   _start, @function
 _start:
        movl    foo@GOTPCREL+4(%rip), %eax
+       movl    foo@GOTPCREL+4(%rip), %r26d
        .size   _start, .-_start

diff --git a/gold/x86_64.cc b/gold/x86_64.cc
index 928dfa8..b7be9bf 100644 (file)
--- a/gold/x86_64.cc
+++ b/gold/x86_64.cc
@@ -1053,8 +1053,9 @@ class Target_x86_64 : public Sized_target<size, false>
     gold_assert(gsym != NULL);
     // We cannot do the conversion unless it's one of these relocations.
     if (r_type != elfcpp::R_X86_64_GOTPCREL
-        && r_type != elfcpp::R_X86_64_GOTPCRELX
-        && r_type != elfcpp::R_X86_64_REX_GOTPCRELX)
+       && r_type != elfcpp::R_X86_64_GOTPCRELX
+       && r_type != elfcpp::R_X86_64_REX_GOTPCRELX
+       && r_type != elfcpp::R_X86_64_CODE_4_GOTPCRELX)
       return false;
     // We cannot convert references to IFUNC symbols, or to symbols that
     // are not local to the current module.
@@ -2971,6 +2972,7 @@ Target_x86_64<size>::Scan::get_reference_flags(unsigned int r_type)
     case elfcpp::R_X86_64_GOTPCREL:
     case elfcpp::R_X86_64_GOTPCRELX:
     case elfcpp::R_X86_64_REX_GOTPCRELX:
+    case elfcpp::R_X86_64_CODE_4_GOTPCRELX:
     case elfcpp::R_X86_64_GOTPLT64:
       // Absolute in GOT.
       return Symbol::ABSOLUTE_REF;
@@ -3251,6 +3253,7 @@ Target_x86_64<size>::Scan::local(Symbol_table* symtab,
     case elfcpp::R_X86_64_GOTPCREL:
     case elfcpp::R_X86_64_GOTPCRELX:
     case elfcpp::R_X86_64_REX_GOTPCRELX:
+    case elfcpp::R_X86_64_CODE_4_GOTPCRELX:
     case elfcpp::R_X86_64_GOTPLT64:
       {
        // The symbol requires a GOT section.
@@ -3261,21 +3264,30 @@ Target_x86_64<size>::Scan::local(Symbol_table* symtab,
        // mov foo@GOTPCREL(%rip), %reg
        // to lea foo(%rip), %reg.
        // in Relocate::relocate.
+       size_t r_offset = reloc.get_r_offset();
        if (!parameters->incremental()
-           && (r_type == elfcpp::R_X86_64_GOTPCREL
-               || r_type == elfcpp::R_X86_64_GOTPCRELX
-               || r_type == elfcpp::R_X86_64_REX_GOTPCRELX)
+           && (((r_type == elfcpp::R_X86_64_GOTPCREL
+                 || r_type == elfcpp::R_X86_64_GOTPCRELX
+                 || r_type == elfcpp::R_X86_64_REX_GOTPCRELX)
+                && r_offset >= 2)
+               || (r_type == elfcpp::R_X86_64_CODE_4_GOTPCRELX
+                   && r_offset >= 4))
            && reloc.get_r_addend() == -4
-           && reloc.get_r_offset() >= 2
            && !is_ifunc)
          {
            section_size_type stype;
            const unsigned char* view = object->section_contents(data_shndx,
                                                                 &stype, true);
-           if (view[reloc.get_r_offset() - 2] == 0x8b)
+           if (r_type == elfcpp::R_X86_64_CODE_4_GOTPCRELX
+               && view[r_offset - 4] != 0xd5)
+             goto need_got;
+
+           if (view[r_offset - 2] == 0x8b)
              break;
          }
 
+need_got:
+
        // The symbol requires a GOT entry.
        unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
 
@@ -3498,6 +3510,7 @@ Target_x86_64<size>::Scan::possible_function_pointer_reloc(
     case elfcpp::R_X86_64_GOTPCREL:
     case elfcpp::R_X86_64_GOTPCRELX:
     case elfcpp::R_X86_64_REX_GOTPCRELX:
+    case elfcpp::R_X86_64_CODE_4_GOTPCRELX:
     case elfcpp::R_X86_64_GOTPLT64:
       {
        return true;
@@ -3714,6 +3727,7 @@ Target_x86_64<size>::Scan::global(Symbol_table* symtab,
     case elfcpp::R_X86_64_GOTPCREL:
     case elfcpp::R_X86_64_GOTPCRELX:
     case elfcpp::R_X86_64_REX_GOTPCRELX:
+    case elfcpp::R_X86_64_CODE_4_GOTPCRELX:
     case elfcpp::R_X86_64_GOTPLT64:
       {
        // The symbol requires a GOT entry.
@@ -3736,8 +3750,12 @@ Target_x86_64<size>::Scan::global(Symbol_table* symtab,
         size_t r_offset = reloc.get_r_offset();
         if (!parameters->incremental()
            && reloc.get_r_addend() == -4
-           && r_offset >= 2
-            && Target_x86_64<size>::can_convert_mov_to_lea(gsym, r_type,
+           && ((r_type != elfcpp::R_X86_64_CODE_4_GOTPCRELX
+                && r_offset >= 2)
+               || (r_type == elfcpp::R_X86_64_CODE_4_GOTPCRELX
+                   && r_offset >= 4
+                   && view[r_offset - 4] == 0xd5))
+           && Target_x86_64<size>::can_convert_mov_to_lea(gsym, r_type,
                                                            r_offset, &view))
           break;
 
@@ -4420,6 +4438,7 @@ Target_x86_64<size>::Relocate::relocate(
     case elfcpp::R_X86_64_GOTPCREL:
     case elfcpp::R_X86_64_GOTPCRELX:
     case elfcpp::R_X86_64_REX_GOTPCRELX:
+    case elfcpp::R_X86_64_CODE_4_GOTPCRELX:
       {
       bool converted_p = false;